SQLite的增删改查一

一、通常数据库操作会创建一个DAO类

public DBDao(Context context){
	DBOpenHelper dbOpenHelper = new DBOpenHelper(context);
	//writable加锁操作数据库
	//dbOpenHelper.getReadableDatabase();
	//dbOpenHelper.getWritableDatabase();
}

/**
 * 增
 */
public void add(String name){
	SQLiteDatabase db = dbOpenHelper.getWriteDatabase();
	if(db.isOpen()){
		db.execSQL("insert into book(name) values(?)",new Object[]{name});
		db.close();
	}
}

/**
 * 删
 */
public void delete(String name){
	SQLiteDatabase db = dbOpenHelper.getWriteDatabase();
	if(db.isOpen()){
		db.execSQL("delete from book where name=?",new Object[]{name});
		db.close();
	}
}

/**
 * 改
 */
public void update(String name,String newname){
	SQLiteDatabase db = dbOpenHelper.getWriteDatabase();
	if(db.isOpen()){
		db.execSQL("update book set name=?,value=? where name=?",new Objec[]{name,newname});
		db.close();
	}
}

/**
 * 查
 */
public void find(String name){
	SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
	if(db.isOpen()){
		//返回结果集
		Cursor cursor = db.rawQuery("select * from book where name=?",new String[]{name});
		if(cursor.moveToFirst()){
			//name在行中第几列
			int index = cursor.getColumnIndex("name");
			cursor.getString(index);
		}
		cursor.close();
		db.close();
		
	}
}

public List<Book> findAllList(){
	SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
	if(db.isOpen()){
		Cursor cursor = db.rawQuery("select * from book",null);
		while(cursor.moveToNext()){
			int index = cursor.getColumnIndex("name");	
			cursor.getString(index);
		}
		cursor.close();
		db.close();
	}
}